Impact of rdisp/max_wprun_time in Dialog Response Time

[Former Member]

Hi everybody,

I have a client which instances allow dialogue users to run dialogue proceses for 3 hours, we can see that many dailogue processes more than a hour. Do this affects the dialogue response time that we see in transaction st03n???

The SLA for dialogue response time is based on a threshold for maximum number of dialogue steps allowed. Now the dialogue response time is high, and we have attacked issues at other areas like database. But i wonder if the high value for rdisp/max_wprun_time could impact in my response time for dialogue steps.

If so, is there some official information by SAP that explain this???, or is a "Best Practices" document fo this parameter???

Regards,

Christian

[Former Member · Accepted solution]

The default for this parameter is 600. And SAP says that this can be considered a good setting (even if I've found in the "real world" some greater values ). I think that you can explain the customer which the risk is:

If the the value is greater than a reasoneable time, the customer may fall in this scenario:

all the dialog work processes become busy and no one can log on into the system because no dialog services are available!

this parameter let SAP "kills" a process that take too long in a dialog wp, to let this one take in charge new diag requests from other endusers.

For sure a dialog application that take more than 300 secs should be checked against a performance analysys (a code review, new secondary index and so on).

ciao

Marco

[former_member185954]

Hi Christian,

Here is a rough guide for good response time:

http://help.sap.com/saphelp_47x200/helpdata/en/c4/3a6af1505211d189550000e829fbbd/frameset.htm

About your question whether the parameter can affect response time, the answer depends on whether you have high Average Wait time, if the Average Wait time is high, this means your programs or user sessions have to wait for a longer time to get free dialog processes, which means your dialog processes are frequently locked up in long running transactions or maybe there are insufficient number of dialog processes at any given time even if all of them are not locked in long running transactions!

So check your system if you find long running dialog transactions frequently the wp_runtime parameter will definitely have an effect on the response. If your system doesn't have frequent long running dialog transactions this parameter won't have any effect, you may then consider increasing dialog processes to serve your users better

Hope that helps,

Regards,

Siddhesh

Regards,

Siddhesh

[Former Member]

Hello,

I have read the following in another post:

<b>The current setting is 300 seconds. After this, the system gives the program a second chance. During the first half (>= 300 seconds), a call that is blocking the work process (such as a long-running SQL statement) can occur. While the statement is being processed, the database layer will not allow it to be interrupted. However, to stop the program terminating immediately after the statement has been successfully processed, the system gives it another 300 seconds.

Hence the maximum runtime of a program is at least twice the value of the system profile parameter "rdisp/max_wprun_time".</b>

Does any know if this is correct?

[Former Member]

Hi,

This is nearly true.

For an abap program without SQL request (very unusual), the max runtime will be 300 s.

For an abap program with short SQL requests, the max runtime will be a little more than 600 s.

For an abap program with a several hours SQL request, the max runtime will be several hours.

It means that the rdisp/max_wprun_time parameter is not the ultimum protection but it is very very useful...

Regards,

Olivier

[Former Member]

Do you know any sap note or documentation to deepen this issue??

I want to know if there is a direct impact of high values of rdisp/max_wprun_time parameter (which allows long running dialog processes) in overall dialog response time. Of course, the recommended behaviour is running these processes as batch.

What i mean....If a dialogue process than runs for two hours, took 90% of the time in an expensive sql statement, do this time is assigned to the response time of the dialog process when estimating the overall dialog response time in st03n or not???

What parts of time are exactly measured in a dialog process??

Regards

[Former Member]

Hi

Dispatcher wait time

Roll in time recommendation is <50ms

Roll out time recommendation is <50ms

Process time should be less than twice the CPU time or less than 200ms

Enqueue time

CPIC / RFC

Load and generation time

DB time

All the compnents time is the average response time

SAP recommends good response time of a SAP system is 800 to 1200ms

Cheers,

Shyam.

[Former Member]

Yes, the response time will be bad in this case. Any long preocesses should be run in background and never in dialog.